The present invention relates to fuel cell systems and more particularly to a fuel cell system with increased efficiency and method of operating the fuel cell system.
Fuel cell systems, for example PEM fuel cells connected together to form a fuel cell stack which serve for the generation of electrical energy, for example electrical drive energy for a motor vehicle are known in the art. The fuel cell stacks include an anode inlet for a fuel, such as hydrogen and a cathode inlet for oxygen, for example in the form of atmospheric oxygen. The oxygen is delivered by a compressor driven by an electric motor which is operated with the electrical energy generated. A cooling system is provided for carrying away heat generated in the fuel cell stack and in doing so determines the respective operating temperature of the fuel cell stack.
Current fuel cell systems operate at fixedly pre-set design values for the operating temperature and operating pressure of the system. The operating pressure is typically pre-set within very tight limits. Although the present invention is not limited to structure or steps that satisfy any specific needs, it is noted that the present inventors have recognized a need in the art for a method of operating a fuel cell system with operating parameters that are not pre-set design values so that the fuel cell system may operate in a more efficient manner. There is also a need in the art for a fuel cell system capable adjusting the values of the operating parameters so that the fuel cell system may operate in a more efficient manner.